<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .box {
      width: 200px;
      height: 100px;
      background-color: pink;

      /* 使用动画 */
      animation: change 2s;
    }

    /* 定义动画：从200变大到600 */
    /* @keyframes change {
      from {
        width: 200px;
      }

      to {
        width: 600px;
      }
    } */

    /* 定义动画：从200 到 500*300 到 800*500 */
    /* 百分比指的是动画总时长的占比 */
    @keyframes change {
      0% {
        width: 200px;
      }
      50% {
        width: 500px;
        height: 300px;
      }
      100% {
        width: 800px;
        height: 500px;
      }
    }
  </style>
</head>

<body>
  <div class="box"></div>
</body>

</html>